Interpretive Summary: Vitamin A (VA) deficiency is a worldwide public health problem in more than 118 countries; 100 to 140 million children are VA deficient. Of those VA-deficient children, up to 500,000 children will become blind every year; half of those children will die within 1 year of losing their sight. Plant orange pigments, called carotenoids, are a major source of dietary VA in a large proportion of the world's population. One long-term solution proposed to combat VA deficiency is gardening and preserving fruits and vegetables in order to maintain VA status. Carrots are grown worldwide and a strain of carrots genetically selected to have carotenoid content was developed in hopes of improving VA status in deficient areas of the world. Several studies show that the Mongolian gerbil (Meriones unguiculatus) is an appropriate model to investigate carotene metabolism to predict how humans may metabolize this important nutrient. The present study reports the relative metabolism of carotenoids from carrots in two studies in Mongolian gerbils. It demonstrated that gerbils are an excelent organism to model metabolism similar to humans, and it demonstrated that carrots with higher carotene content have a greater vitamin A nutritional impact than those with less carotene. This study is of interest to nutritionists and vegetable growers and breeders intertested in the nutritional impact of vegetable crops.

Technical Abstract:
Vitamin A (VA) deficiency is a worldwide public health problem. Biofortifying existing sources of beta-carotene (betaC) and increasing dietary betaC could help combat the issue. Two studies were performed to investigate the relative betaC bioavailability of a betaC supplement to purple, high-betaC orange, and typical orange carrots using Mongolian gerbils (Meriones unguiculatus). In study 1, which used a traditional bioavailability design, gerbils (n 32) received a diet containing orange, purple, or white carrot powder, or white carrot powder +a betaC supplement. In study 2, which included betaC-biofortified carrots, gerbils (n 39) received orange, high-betaC orange, purple, or white carrot powder in their diet. Both studies lasted 21 d and the gerbils were killed to determine the effect of carrot type or supplement on serum and liver betaC, alpha-carotene, and VA concentrations. Liver stores of betaC or VA in the gerbils did not differ between orange and purple carrot diets when equal amounts of betaC from each of the diets were consumed (P> 0.05). Both the orange and purple carrot diet resulted in higher liver VA compared with the supplement (P< 0.05). High-betaC carrots resulted in more than 2-fold higher betaC and 1-1 times greater VA liver stores compared with typical orange carrots (P<0.05). These results suggest that high-betaC carrots may be an alternative source of VA to typical carrots in areas of VA deficiency. Second, phenolics including anthocyanins and phenolic acids in purple carrot do not interfere with the bioavailability of betaC from purple carrots.